Field of the Invention
The present invention relates to wireless communication, and more particularly, to a method for moving carried out in a wireless communication system and an apparatus supporting the same.
Related Art
3GPP (3rd Generation Partnership Project) LTE (long term evolution) which is improvement of UMTS (Universal Mobile Telecommunications System) has been introduced as 3GPP release 8. The 3GPP LTE uses OFDMA (orthogonal frequency division multiple access) in a downlink, and uses SC-FDMA (Single Carrier-frequency division multiple access) in an uplink. The 3GPP LTE adopts MIMO (multiple input multiple output) having maximum four antennas. Recently, a discussion of 3GPP LTE-A (LTE-Advanced) which is the evolution of the 3GPP LTE is in progress.
The wireless communication system can support providing a service through a plurality of access networks to the terminal. The terminal can receive the service from a 3GPP based access network such as a mobile wireless communication system and further, receive a service from non-3GPP based access networks such as Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), and the like.
In a wireless communication system, a terminal can change an access network providing a service according to a wireless environment such as the quality of the service which can be provided from the access network or a load of the access network and this is referred to as movement of the terminal. The terminal can receive the service through movement such as changing a serving cell on a 3GPP access network or newly accessing a non-3GPP access network.
The terminal needs to determine the non-3GPP access network positioned therearound in order to efficiently offload some or all traffic being transmitted/received or to be transmitted/received in the 3GPP access network to the non-3GPP access network. Service coverage of the non-3GPP access network such as a WLAN access network may be still smaller than macro cell coverage of the 3GPP access network. Therefore, the terminal needs to continuously activate a module for non-3GPP communication and perform detection in order to discover the non-3GPP access network and effectively offload traffic by using the discovered non-3GPP access network. However, this can rapidly consume power of the terminal. In order to prevent the rapid consumption of the power, the terminal needs to intermittently perform detecting the non-3GPP access network.